Wireless communication devices that are designed for mobile applications are typically implemented as short-range, short-lived connections. To establish connection, wireless devices utilize a protocol that includes discovery, service query, connection request, connection response, and connection. In addition, some protocols include a security phase, in which an authentication algorithm is used to verify the validity of the requesting device.
Discovery is the process of determining which devices are currently within range. Typically, the initiator of the discovery exchanges device addresses and other information with the responder.
A portable device can potentially encounter several devices which roam in and out of range. A device in search of services is often called a client. A device that offers the services is known as a server. Clients in constant search of a new domain will periodically discover what devices are in range. Examples of server devices include internet gateways, vending machines, printers, and other public service machines.
When new devices are found, a portable roaming device will perform a service query to ascertain what services are available on the new devices. The service query involves establishing a connection to the new device at a well known service access point and exchanging database queries and responses in a format appropriate for the protocol. The response to a discovery, the negotiation of a connection to the service database, and the exchange of information all require bandwidth.
Further, the responding device uses bandwidth in executing the protocol, searching its database, and formatting a response. One disadvantage of the prior art is that as personal information devices proliferate, and contain more and more ad-hoc wireless protocols, the possibility that hundreds of devices come into range, and each device must query all of the others, and collect service information, is high. As a result, an enormous amount of bandwidth will be required to execute the protocol, search the database, and format a response for each and every request.
In addition, power is consumed in sending responses. Wireless communication devices mostly communicate either through radio or optical links. Radio links typically use a baseband protocol engine and a radio transceiver. One example of a radio link is Bluetooth.
In contrast, optical links are usually achieved through infrared light. The Infra-red Data Association (IrDA) has a defined standard for linking two devices at any data rate up to the current maximum data rate of 4 Mbps. The power required to transfer either radio frequency energy or infrared energy is considerable. Therefore, responding to hundreds of service requests will also greatly reduce the battery life of devices.